Pressure equalizing valve for well strings



April 20, 1954 E. POTTS PRESSURE EQUALIZING VALVE FOR WELL'STRINGS Filed May 12, 1951 3 sheets sheet l Ernesf L. Pal fa INVENTOR.

A TTORNEY PRESSURE EQUALIZING VALVE FOR WELL STRINGS Filed May 12, 1951 5 Shets-Sheet 2 Erneof L. Fozzis' INVENTOR.

Patented Apr. 20, 1954 PRESSURE EQUALIZING VALVE FOR WELL STRINGS Ernest L. Potts, Houston, Tex., assignor to Cicero C. Brown, Houston, Tex.

Application May 12, 1951, Serial No. 226,041

Claims.

This invention relates to pressure equalizing valves and particularly to a pressure equalizing valve adapted for installation in a pipe string employedfor operating tools in a well, such as an oil well or the like, which contains fluid or through which fluid is circulated during operation of the tools. I

In many operations conducted in a well, such as fishing, liner pulling, cutting, etc, the tools employed are ordinarily connected to a string of pipe which is employed to raise and lower the tools, to manipulate the tools, and to conduct fluid to the tools for operating them by hydraulic pressure, or for circulating fluid through the pipe and the surrounding well bore for washing-over objects which have been stuck or lost in the well, or for other purposes well-knownin the art.

' Many of such operations are conducted during the course of drilling and often when the well bore is in communication with earth formations containing gas, oil or water underhigh pressure, so that the well bore must ordinarily be kept filled with high specific gravity liquids, such as mud-laden liquids, so as to maintain a relatively high hydrostatic head in the Well in order to prevent blow-outs by the high-pressure connate fluids in the earth formations, during the operations being conducted in the well. The danger of such blow-outs and other related hazards is greatest while running in and withdrawing the tool string due to the swabbing and pumping action of the withdrawal and insertion operations. Also, when withdrawing a hollow operating string, the bore of such strings will often be filled with the hydrostatic liquid trapped within the string, and as the string must be withdrawn in sections, the liquid in the withdrawn sections will spill therefrom as the sections are broken apart at the top of the well. This results in the loss of relatively expensive weighting fluid, dangerous reduction in the hydrostatic head'in the well, and the creation of unpleasant and dangerous working conditions for the men operating the tools at the top of the well.

Accordingly, the present invention has for its principal object the provision of a valve structure which is adapted to be installed in the operating pipe, and which may be opened andclosed by a simple manipulation of theoperating pipe, in order to open and close communication between the operating pipe and the well bore, as may be required or desirable to obviate the undesirable conditionsnoted above.

. An important object is to provide a valve structure of. the kinddescribedwhich may beopeued 2 and closed by rotation of the operating pipe in one direction only.

Another object is to provide a valve structure including a body adapted to be installed in'the operating pipe string and having radial openings, and a sleeve-type closure therefore frictionally engageable with the wall of the well bore and operable by relativelongitudinal and rotational -movement between the body and the closure to open and close the ports in the body.

A more specific object is to provide a series oflatching elements between the body and closure which are relatively so positioned and constructed as to permit opening and closing of the valve with a minimum amount of manipulation of the operating string and with assurance that the valve is effectively open or closed, as the case may be.

Other and more specific objects and advantages of this invention will become more readily apparent from the following detailed description when read in conjunction with the accompanying drawings which illustrate one embodiment in accordance with this invention. I

In the drawings:

Fig. 1 is a View showing the valve device installed in an operating pipe string extending I into a well and connected to a tool such as a liner-pulling tool; L

Figs. 2 and 2A together constitute an enlarged longitudinal quarter-sectional view of the valve structure showing the parts thereof in the positions when the valve is closed; I

Fig. 3 is a cross-sectional view on line 3-3 of Fig. 2; v

Fig. 4 is a cross-sectional view on line Fig. 2A; and

Figs. 5 and 5A are longitudinal quarter-sectional views generally similar to Figs. 2 and 2A but showing the partsin the positions when the valve is open.

In Fig. 1, the valve device in accordance with the present invention, designated generally by the numeral H), as shown installed in an operating pipe string II, which may bea conventional drill stem or any other suitable tubular pipe string ordinarily employed in well operations and extending into the boreof a wel1l2,

which may be lined with the usualcasing 12a. The lower end of pipe string l I may be connected to a tool, designated generally by the numeral 13, which is to be operatedv by manipulation .of the pipe string or by hydraulic fluid conducted through the boreof the pipe string and ordinarily mug d; martin ush; b gums .l gt. hown a the surface. Tool l3 in Fig. 1 is a, liner pulling tool, such as that described in my co-pending application, Serial No 139,267, filed January 18, 1950, which is adapted to be operated by hydraulic pressure fluid supplied through an operating pipe, such as pipe string II. It will be understood, however, that tool I3 may be any other type of tool commonly employed for conducting operationsin the well, such tool, of itself, forming no part of the present invention.

Valve device is composed of a tubular body I4 having a conventionalthreaded connection at its upper end for connecting the upper end of the body into pipe string I I. At a point beginning somewhat below its upperendybodylkis reduced in diameter to its lower end, to provide a reduced cylindrical portion ll, andthereby forming a downwardly facing annular shoulder 16 at the upper end of reduced portion ll. At

its lower end, reduced portion I1 is externally threaded at I8 and screwed into a'sub' or collar 19 of somewhat larger diameter than-reduced portion Il -the upper-end of collar 19 forming an upwardlyiacing shoulder 20. The diameter of collar 19: will preferablyhave the'same diameter as the upper portion of body 14. Collar l9 forms: means for connecting the lower .end of body [4 into, the pipe string so as to become a part thereof. andsbody "I4.is provided with a bore 2l which registers with the bore of pipe string II and forms, a continuous part thereof. A plurality of angularly spaced ports-22 isprovided in the wall of portion IT. at a level somewhat below shoulder 16.

.It will; be. understood that valve device I0 may .be located. at .any desired; point in pipe string H but that ordinarily it-will be positioned at the lower end of the string immediately above tool l3.

A=tubular sleeve 23, substantially shorter in length'than reduced portion I1, is arranged for longitudinal sliding movement thereon and has mounted on the exterionthereoi-a plurality iof angularly spaced friction::members 24 adapted to frictionally engage casing 12a, lining the wall .of well 12. r :1 Friction members may be in the formeoi the well-known:bowzsprings, as illustrated; or .may bevaof anyother conventional form adapted to frictionally engage, the well wall'for :the' purpose. oi, holding sleeve 23 stationary while .:permitting body |4 .-.to engage in longitudinal;= .or rotational movement relativethereto. Sleeve.,23

is adapted to iormaclosurefor ports. 22, open- :ing and;.iclosing;..of .-..:the. :ports; being effected by longitudinal movement of body I4 relative; to the :sleeve.

The upper portion of the bore of,sleeve.23jis enlargedto forman annularstufiing' box 25 in which :mounted packing, rings 261-26, spaced ;=;apartglongitudinallyzby; means ofv a metal spacing collar 2'! so that the packing rings will-be positionedzabove-and belowports 22 when sleeve 23 is in the-valveeclosingposition, as shownin Fig. 2. A..threaded;gland.;ring 281s screwed into the upper end ;of stuffing. boxi25 to. compress the packing. rings longitudinally whereby to ,cause them to. expand radiallyinto-fluid-tight sealing engagement between the exterior of portion l1 ...and the. .opposite wallof stufilng box 25. Packing rings 26 may be constructed of any conventional type of flexible packing. material but are preferably of the-welleknown' self -actuating, .marginal lipconstruction whereby fluid pressure. exerted ment with the adjacent walls of the bodies between which the packing is to form a seal, while still permitting sliding movement between the bodies. The wall of spacer collar 2'! is preferably made somewhat narrower than the width of stufdng box 25 and is provided with one or more small ports 29 adapted to transmit fluid pressure from the bore of spacer collar 27 to the exterior thereof so that equalized fluid pressure may be exerted on both the inner and outer marginal lips of packing rings 26-26 to assure that both will be effectively actuated at all times.

Portion I! is provided, between ports 22 and shoulder 20, with upper and lower longitudinally spacedrecesses 30 and 3i, respectively, the bottoms of whioh are provided with upper and lower r and is preferablyexternally dimensioned to form a flush extension of the lower end of sleeve 23, and is internally dimensioned to provide an annular chamber which maybe provided with an internal annular flange 36 intermediate the ends of cage 34. The lower .end of cage 34 is closed by an annular bushing 31 which is screwed .-.into the end of the cagev and slidably surrounds @reduced portion l1.

7 Mounted in the upper portion of chamber 35,

surrounding portion I1, is a latching collar 38,

,of a generally downwardly and inwardly taperof complementary .arcuate segments i g, frusto-conical form, composed of a plurality 3$39 s which are provided internally at their lower ends threads of'upper threaded section 32.

with threads 40 adapted to complement the A circulower end, and normally acts to resiliently urge ,the lower ends of segments 39-39 radially inwardly into circumferential end-to-end arrangement, whereby to form-the continuous collar 38, butwhich'willalso allowsome degree of radial --outward-. movement-of segments 3%.

The upper ends of segments 39 are rounded, as at as, and are pivotally seated in an annular groove 4 5 provided inqthe lower end of sleeve 23. Groove 4 1 is arcuatein crosssection and has a radius somewhat greater than that of the rounded ends 43 so as to permit a degree of pivotal movementof segments 39in groove 44. A plurality of angularly spaced guide pins 45 project inwardly from the wall .of cage 34.and are adapted .to extend into holes provided in segments 39 above garterspring 4|. Holes lfi are madeslightly larger. in diameter than guide pins' 45 so as to permit the desired degree of pivotal movement of segments39-while preventing relative rotation between the segments and cage 34.

In the lower-portion of chamber 35 below flange 36there is mounted a second latching collar 33a,

of substantial identical construction to collar 33 but tapering upwardly, and composed of a plurality of complementary arcuate segments 39w- 39a which are provided internally at their upper ends with threads-40a adapted to complement the threads of lower threaded section 33. A

garterspring4la :is seated in a spring-receiving -*'groove'42a cut in the outerwall of collar- 3 8a provided in the upper end of bushing 31 and I having a somewhat larger cross-sectional radius than rounded ends 43a. Guide pins 45a project inwardly from the wall of cage34 and cooperate with holes 46a in segments 39a for the same purpose, and in the same manner as pins 45 and holes 46.

The threads forming upper threaded section 32 are preferably of the upwardly-facing buttress type adapted to lock with threads 4!] on segments 39 to prevent upward movement of body l4 relative to latching collar 38, while permitting downward movement of the body relative to the collar in response to a downward force onbody l4 great enough to overcome the inward radial pressure of garter spring 4!. The threads forming lower threaded section 33 are likewise of the buttress type but are downwardly facing so as tolock with threads 400, on" segments 39a to prevent downward movement of body [4 relative to latching collar 38a while permitting upward movement of the body relative to latching collar 38 a by outward displacement of segments 3911 against the resistance of spring 4hr. It will be understood that when threads 40 are engaged with the left hand threads of upper threaded section 32, and sleeve 34 is held against rotation, right-hand rotation of body I4 will cause sections 32 to screw upwardly through threads 40, thereby releasing body [4 for upward movement relative to sleeve 34. Likewise, when the righthand threads of lower threaded section 33 are engaged with threads 40a on segments 39a, righthand rotation of body I4 will screw the latter downwardly through segments 39: thereby releasing the body for downward movement relative to sleeve 34. The number of threads 43 and 40a is preferably less than the number of threads constituting threaded sections 32 and 33, respectively. From the foregoing, it will be understood that latching collars 38 and 38a may operate, in cooperation with the respective threaded sections 32 and 33, both as screw collars or as ratchetand-pawl connections between body l4 and the valve closure formed by sleeve 23 and cage 34. Since threaded sections 32 and 33 are more-dis tantly spaced apart longitudinally than collars 38 and 38a, only one of the threaded sections can be engaged with only one of the collars at any position.

The above-described device may be operated in the following manner: Valve device Ill will be installed in pipe string ll, having tool 13 con-' nected below valve device l0, all as generally illustrated in Fig. l. Prior to running the tool strin into a well,'sleeve 23 and cage 34 will be set in the downward position on body l4'to' open ports 22, the parts of the valve structure being in the positions shown in Fig. l, and particularly in Figs. and 5A. At this stage, it will be noted that lower threaded section 33 will be engaged with threads 43a of latching collar 38a while latching collar 38 will be below upper threaded section 32. As the device is run into the well, the engagement of segments 39d will act as spring-pressed pawls having threads 40a engaged with the downwardly facing buttress threads of lower threaded section 33 to prevent downward movement of body l4 relative to the closure sleeve,

6. so that theposition ofthelatter on body 14 will be fixedthroughout the downward movement in.

the well, the frictional engagementof friction members 24 with the wall of the well acting in opposition to the downward movement of body. l4 to intensify theengagement. between threads m and threaded section 33. With ports 22 .thus open, the interior of the tool string will be open' tothe well bore so as to allow fluid in the well bore, through which the string descends, to flow. upwardly through bore 2| and out through ports 22 into the well bore, thereby continuously maintaining. balanced fluid pressure inside and outside the tool string while the string descends, thus allowing the tool string to descend freely. and avoiding a. piston effect on the well bore fluid below the tool.

When the tools have attained the desired. point in the wellat which they areto be operated and it is desired to close ports 22 in order that fluid may be pumped through the bore of the string to operate tool l3 or for any other purpose, the upper end of pipe string II will be rotated in the right-hand direction. Since the threads of 10wer threaded section 33 are left-hand threads, right-hand rotation of the pipe string will cause lower threaded section 33 to screw downwardly through the threads on latching collar 38a. The latter will, of course, remain stationary, being connected throughpins a to cage 34 and sleeve 23 which will be held against rotation by the frictional engagement of friction members 24 with the wall of the well. When threaded section 33 has thus been screwed entirely through latching collar 38a, the tool string and body l4 will be released for further downward movement relative tosleeve 23 and will then be lowered until shoulder It comes down against the upper end of sleeve 23, at which point packing rings 26-46 will be in position above and below ports 22, as best seen in Fig. 2, thereby closing these ports. At the same time upper threaded section 32 will have been caused to slide downwardly through latching collar 38. Due to the relative shapes of. the'threads of threaded section 32 and threads 40 on segments 39, the latter will be thrust radially outwardly by the weight of the tool string which will overcome the resistance of spring 4| so as to allow the necessary degree of outward movement of the collar segments.

Threaded section 32 is so positioned on reduced portion I! of the body relative to shoulder [6, that when the upper end of sleeve 23 is a ainst shoulder 16, threads 40 will be in registration with some of the threads on section 32, preferably the lower ones, and will be in threaded engagement therewith, thereby locking closure sleeve 23 to body l4 with ports 22 closed. Latching'collar 38a will be positioned between threaded sections 32 and 33, as shown in Fig. l. Fluid may now be pumped through the bore of the pipe string to the tool for operations as desired.

When it is desired to withdraw the string of tools from the well and to open ports 22 before doing so, the upper end of pipe string II will again be rotated to the right, which, by reason of the left-hand threads of threaded section 32, will cause this threaded section to screw upwardly through the threads on segments 39, an upward pull being maintained at the same time on the pipe string. As soonas threaded section 32 has cleared the threads on segments 39, the pipe string may be drawn upwardly through the closure'elements until the lower end of bushing 31 at the bottom of cage 34 strikes shoulder 20,

atwhichpoint threads Alla, .onzsegments 39a-will again engage .threaded section 33, which because of the shape of its threads .relative to threads 40a, will be able to slide upwardlythrough segments. 39a. whiohwill be forced outwardly against the .resistance of garter spring 41a to allow upward passage therethrough of threaded section 33. It willbe understood that threaded section 33 will be so positioned longitudinally above shoulder 20 that when bushing ("rests on shoulder 20, threads 40a willbe in registration with :some of the threads 40 on section. 33, preferably the upper ones, and in. threaded engagement therewith. Closure sleeve 23 will thus again be locked in its downward positionon body It at which ports 22 will again be open, as in Figs. and 5A. The pipe string and its. attached tools may now be drawn upwardly from the well, and open communication: will. be provided through ports 22 between the interior of the pipe string and the well, so that as the pipe string is drawn out or" the well, any fluid trapped in the interior thereof will .fiow out through ports 22 into the well bore. In this way no fluid will be lifted out of the well bore by the emerging pipe but will instead remain in the 'well bore to thus maintain full hydrostatic head of the column of fluid on the earth formations penetrated by the well. The pressure will be continuously equalized between the interior of the pipe string and the well bore throughout the withdrawal operation, and swabbing action by the upwardly moving tools will be obviated.

It will be understood that by the described construction, the valve may be either open or closed when the tool string is run into, or withdrawn from, the well, as may be desired. It will also be seen that locking of the valve in the open or closed position is effected automatically, thereby avoiding the necessity of hunting the proper locking and unlocking positions, as required in more conventional tools, and that both the opening and closing of the valve may be effected by rotation of the operating pipe in the same direction, generally the righthand direction, which has the advantage that such rotation will al ways be in the direction which will tighten the usual screw connections between sections of the operating pipe string.

It will be understood that numerous alterations and changes may be made in the details of the illustrative embodiment within the scope of the appended claims without departing from the spirit of this invention What I claim and desire to secure by Letters Patent is:

l. .A pressure equalizing valve for well strings, comprising, a tubular body having radial ports through the wall thereof, a tubular sleeve rotatably mounted on said body and slidably movable thereon between positions for opening and closing said ports, friction elements secured to said sleeve and extending into frictional engagement with a well wall to hold said sleeve against rotation on said body, laterally extending abutment members on said body on opposite. sides of said ports to limit longitudinal movement of the sleeve relative to the body, a pair of longitudinally spaced external thread sections on said body between said ports and the lower abutment member, and a pair of longitudinally spaced pawl members pivotally mounted on said sleeve for radial movement relative to said thread sections and releasably engageable therewith in response 8. to relative movement betweensaid :body and said sleeve, the longitudinal spacing betweenthe pawl members being less than that between-said thread sections.

2. A pressure equalizing valve for well strings, comprising; the'tubular body having radial ports through the wall thereof, atubular sleeve rotatably mounted on said body and slidably movable thereon between positions for opening and closing said port-s, friction elements secured to said sleeve and extending intofrictional engagement with a'well wall to hold said sleeve against r0- tation on said body, a pair of longitudinally spaced external thread sections on said body below said ports, and a pair of longitudinally spaced pawl members pivotally mounted on said sleeve for radial movement relative to said thread sections and releasably engageable therewith in response to relative movement between said body and said sleeve,-the longitudinal spacing between said pawl members being less than that between said thread sections.

3. A pressure equalizing valve according to claim 2 wherein said pawl members are provided at their axially adjacent end portions with internal threads complementary in shape to the threads of said thread sections.

4. A pressure equalizing valve according to claim 2 wherein said pawl members. comprise segmental frusto-conical collars'surrounding said body, the smaller ends of which are directed toward each other and are provided with internal threads complementary in shape to the threads of said thread sections.

5. A pressure equalizing valve according to claim 2 wherein said pawl members comprise segmental frusto-conical collars surrounding said body, the smaller ends of which are directed toward each other and are provided with internal threads complementary in shape to the threads of said thread sections, and resilient means normally urging thesegments of the collar radially inwardly toward said body.

6. A pressure equalizing valve according to claim 2 wherein the bore of said sleeve is provided with annular packing elements spaced apart longitudinally to form seals between said sleeve and said body 'above and below said ports when said sleeve is in the port-closing position.

7. A pressure equalizing valve for well strings, comprising, a tubular body having radial ports throughthe wall thereof, a tubular sleeve rotatably mounted on said body and slidably movable thereon b-etweenpositions for opening and closing said ports, friction elements secured to said sleeve and extending into frictional engagement with a well wall to hold said sleeve against rotation on said body,. a pair of longitudinally spaced external thread sections on said body below said ports, the upper one of said thread sections being composed of left-hand upwardly facingbuttress threads and the lower one of said thread sections being composed of righthand downwardly facing buttress threads, a pair of longitudinally spaced pawl members pivotally mounted on said sleeve for radial movement relative to said thread sections and releasably engageable. therewith in response to relative movement between said body and said sleeve, said pawl members having internal threads complementary in shape to the threads of said thread sections, the longitudinal spacing between said pawl members being less than that between said thread sections.-

8. A pressure equalizing valve according to claim 7 wherein said pawl members comprise segmental frusto-conical collars surrounding said body having their smaller ends directed toward each other, and resilient means normally urging the segments of said collar radially inwardly toward said body.

9. A pressure equalizing valve according to claim 7 wherein the bore of said sleeve is provided with annular packing elements spaced apart longitudinally to form seals between said sleeve and said body above and below said ports when said sleeve is in the port-closing position.

10. A pressure equalizing valve according to claim 7 wherein said body is provided with laterally extending abutment members located on 10 said body respectively above said ports and below the lower one of said thread sections to limit the longitudinal travel of said sleeve relative to said body.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,593,909 Nixon July 2'7, 1926 1,892,636 Slater Dec. 27, 1932 2,155,380 Bean Apr. 25, 1939 2,207,448 Ashbrook July 9, 1940 2,352,700 Ferris July 4, 1944 

